Eelgrasses are submerged rhizomatous (but not tuberous) aquatic plants, producing rosettes of long strap-like leaves which can vary in length from a few centimetres to 5.5 metres in deep water. Rooted or anchored in sediment they have no leafy stem; leaves all arise from a basal rosette at the sediment surface. Leaves have many small longitudinal veinlets and cross-septa, from 0.4-1cm wide. Plants form stout rhizomes that extend from the sediments. Numerous roots, up to 40cm long, sprout at each leaf-bearing node on the rhizomes (Greater Wellington Regional Council 2004b). The sexes are on different plants, the male flowers released and free-floating and the female with a spiral peduncle.
Juvenile or sterile specimens may be difficult to distinguish (Warrington 1994).
Vallisneria nana has been reported to flower abundantly in Auckland, New Zealand from November to March (Coffey and Clayton 1987). However, please note that in New Zealand there is no evidence of viable seed being produced (Greater Wellington Regional Council 2004b).
Compiler: IUCN/SSC Invasive Species Specialist Group (ISSG) with support from the Terrestrial and Freshwater Biodiversity Information System (TFBIS) Programme (Copyright statement)
Review: Dr. Surrey Jacobs Principal Research Scientist Royal Botanic Gardens Sydney NSW, Australia
Publication date: 2006-11-01
Recommended citation: Global Invasive Species Database (2021) Species profile: Vallisneria nana. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=879 on 19-01-2021.